Process of and apparatus for distilling petroleum.



J. W. VAN DYKk; L W. M. IRISH. PROCESS 0F AND APPARATUS POR DIsTlLLING PRIILOLRUM.

APPLICATION FILED 00124, 1009. 1,073,548. Pamwd sept. 16. 1913.

2 SHEETS HEBT 1.

vwentong,

J. W. VAN DYKE & W. M. IRISH. PROCESS 0F AND APPARATU@| FOR msTILLING PBTHOMUM` APPLICATION PlLED 00124` m09` 1.,O?3,548. manned sept. 16, 1913.

2 SHEETS-SHEET 2,

narran stains ramena? caricia JOHN W. VAN DYKE AND WLLIAM M. IRISH, 0F PHLADELPHIA, PENNSYLVANIA.,

ASSIGNORS T0 THE ATLANTIC REFINING COEIIPANY, OF PHILADELHIA, PENN" SYLVANIA, A CORPORATION OF PENDUSILVANIA.

YROCESS OF AND APPARATUS FOR DISTILLING PETROLEUM.

T0 all whom t may concern Be it known that We, JOHN WV. VAN DYKE and )VILLIAM M. Inisn, both citizens of the United States, residing' at Philadelphia, in the county of Philadelphia and State of Pennsylvania, have invented certain new and useful Improvements in Processes of and Apparatus for Distilling Petroleum, ot' which the following is a spe'cication.

This invention relates more particularly to the distillation of petroleum in the form ot' undistilled residues containing all, or nearly all, the intermediate fraction in addition to the lubricant (or, when the petroleum yields paraiiin wax, the lubricant and WaX yielding.) traction of lthe petroleum, as said fractions are hereinafter detined; hut it extends also to the distillation of undistilled residues resulting from a still 'further evaporation of the crude petroleum, but containing at least forty per cent. o't` said lubricant (or lubricant and wax yielding) traction; and in part the invention extends to the distillation of petroleum in other forms (distillate or undistilled). Each ot the improvements composing the invention is intended to be secured for all the uses to Which it can'be applied, with or Without modication.

In the prior current practice undistilled residues of the kind herein above first mentioned have been distilled partly with a view to lincrtzasing the yield of burning oil (kerosene) by crackimg.,lr decomposable hydrocarbons of' the lower boilingr portion of such residues and partly with a view to obtaining distillate containing the decomposable but undecomposed or only slightly decomposed hydrocarbons of the lubricant (or lubricant and wax yielding) fraction of the crude oil; and the mode adopted for reconciling these to a certain extent inconsistent objects has been to subject such residues' to` distillation first in stills with their topsfexposed (fully or with slight protection only) to the atmosphere for cooling and thus partially condensing the vapors before theypass over to be condensed as distillate (the same still serving both for the precedent distillation of the crude oil or ot a residuethereof and for the cracking operation) and Jthen the remaining portion thereof in stills (termed tar stills) with Specification of Letters Patent.

Application filed October 4, 19094 yielding) somctlmes it has contained the whole of Patented Sept. 1G, Ti 913.

Serial No. 520,937.

their tops protected for keeping the vapors hot, the residuum from the cracking operation being transferred to the tar stills with intermediate cooling, settling' and storage and in the case ot' petroleum obtain-ed from the oil fields of Illinois and ot other petroleum of analogous character also with subjection ol the residual oil to treatment with sulfuric acid or to other special treatment (in addition to settling) for separating therefrom the colte and other heavy products of the crackingr operation. rI he extmit to which the crackingr operation is carried has been regulated according to the judgment of the manufacturer in view ot' market and other conditions. The transferred residuuln or tar has sometimes contained part only of the lubricant (or lubricant and wax fraction of the crude oil and said traction, together with a considerable portion of the intermediate fraction (as these fractions are herein defined).

The condensate which results from cooling' the vapors in the exposed top stills has fallen directly into the liquid oil in dis:l

tillation, or else has run down the still Walls into said oil. The uncondenscd portion of the so cooled vapors has then passed over and been at once condensed (except very light products) by means oi a water cooled condenser. The vapors from the tar stills, on the other hand, after passing' over have been subjected to a series of-two partial condensations in air cooled condensers before their complete condensation (except very light products) in a'water cooled condenser, each partial condensation being effected in a single large pipe inclined upward and cooled merely by exposure to the atmos phere.

At the end of a run, before opening,r the stills for cleaning out, it has been the practice to, fill the same with free steam, in order to expel the hydrocarbon vapors therefrom; and these with the steam have been passed through the condensers employed in the distillations. )Vhon the residual petroleum has been Withdrawn from said exposed top stills much mattei' has bceiileft adherent to the interior of the stills; and there has thus been a direct loss (because the adherent matter is in part at least itself of value) and also an indirect loss because time and labor are required tov clean out the still after each run preparatory to the next.

The necessary cooling ofthe residual oil in prior current practice and itsstorage also involve a loss of time and labor; and there is a further loss of valuable material in the matter which settles out in the storage tanks or is removed by the additional special treatment needed in the prior current practice with petroleum of the kinds o-btained from the oil fields of Illinois, Kansas, Oklahoma and Texas. Moreover, with any given plant., whenever as is often desirable) the distillation in the exposed top stills has been carried farther than or not so far as the point at which no more and no less residuum is made than the tar stills have capacity to distil, a part either of the exposed top stills or of the tar stills of said plant must be idle. Further, fromvarious causes, the separation of hydrocarbons in the partial condensations of said prior current practice has been lvery imperfect. One cause is the lack of control over the cooling eiect produced on the vapors. ADiEerent installations have diered in the area and degree of exposure of the 'air cooled -(condensing) Walls, according to the views of the manufacturer; but with any given installation the 'cooling' effect producedpon the vapors has been customarily controlled solely through regulation of the still fires.` By slackening these, the'rate of evaporation in the still can be lessened; and less heat being then) iniparted by the vapors to the heat conducting walls, these fall in temperature and condense a larger proportion of the passing va pors (although the absolutev volume condensed is smaller than before.) By urging the fires, evaporation is increased ;v and the heat conducting'walls rise inl temperatureand condense a ismallerproportion (but iore absolutely) of the evolved vapors. There are, howeverfvariable conditions in a run or in diiferent. runs, due to the varying temperature of the air or other meteorological conditions and to variations in the oil-in distillation lin a run or to be distilled in different runs, which cannot be met as completely as would be'desirable (if at all) by' regulation of still yfires; and, besides, it is not possible to insure a perfect regulation of them at all times. rlhe cooling also itself of the vapors has not been thorough in prior currentpractice; nor Ahas proper opportunity been afforded foi` interchange of hydrocarbons between the condensate and the vapors.

Various proposals have been made for im- -p'roving the separation of petroleum hydrocarbons by partial condensation of their mixed vapors; but in spite of them the prior current practice has been as stated. By reason of the imperfect separation dierent therein, could be more advantageously uti` lized as constituent-s of other cuts. For eX- ample, hydrocarbons which are sufliciently colorless and are otherwise suited for water white burning o-il (kerosene) distillate are made (as a result of imperfectI separation) to pass into distillate of poorer quality; because they are accompanied by hydrocarbons too highly colored or otherwise unsuited for water white oil. the yield of lubricant stock (or of lubricant stock and wax yielding material) is diminished by imperfect separation; because this results in the first of the desired hydrocarbons being accompanied by hydrocarbons which are undesirable in such stock (or material). Y

By the aid of the present invention, the said products, for the obtainment of which the prior current practice was adopted, can be obtained without the loss of timeand labor and material incident to the customary transfer of residuum in said prior current lin like manner practice and also without the loss in enforced idleness of part of the plant which4 results in prior current practice whenever the tar stills are of insufficient capacity for distilling all the residuuni of `the desired es i character which can'b'e made in the exposed of better quality and in large/r amount than'v in the prior current practice. Moreover,l if' it should be preferred vto obtain distillate A without sov much cracked products, it is possible to do so without necessarily carrying' over into such distillate more than a small` proportion of the lubricant y( or lubricant and 'wax yielding) hydrocarbons. Y

In accordance with the present invention,

crude petroleum is distilled, it may be in -any known or suitable way, until an undistilled residue is obtained of the kind herein above mentioned; and this residue' is then subjected to distillation at the requisite high temperatures uninterruptedly in two stages; the earlier of' which is' conducted with a view to condensing out of thev mixed mass .of vaporszfor return to the oil in distillation those hydrocarbons which it is desired to have in'the lubricant stock (or the lubricant stock' and wax yielding material).'and also those hydrocarbons which it is desired to crack into lighter oil, while allowing the other hydrocarbons to pass over to be con-l `densed as distillate and is terminated while the residual oil yetrepresents a large part at o.

least (not less than 25 per centof the lubricant (or of the lubricant and wax yielding) fraction of the crude oil; and the later iso of which stages is thereupon begun and is conducted with a View to obtaining distillate composed of the decomposable but undecomposed or only slightly decomposed hydrocarbons of said fraction, a suitable temperature difference (say of about 100O F. to 150O F. or more) vfor holding back the desired lubricant (or lubricant and Wax yielding) hydrocarbons being maintained in said earlier stage between the liquid oil in distillation and the vapors passing over to be condensed as distillate, and a less temperature difference being maintained in said later stage between them (say a difference which is smaller than that of the earlier stage by-o F., 75 F., or more). Unless otherwise preferred for special purposes, the distillation, both in the earlier and in the later of said stages, is performed under atmospheric pressure, or nearly so, and Without the injection of steam or other aeriorm fluid into the stills. During the later of )said stages the vapors in the still should be protected against conductive. cooling to the extent at least to which they would be subjected thereto in one of the exposed top stills of prior current practice; because such cooling would needlessly increase the fuel consumption and would provoke a wasteful decomposition of hydrocarbons; and in the earlier stage it is advantageous to protect the vapors in the still against such conductive cooling and to subject them after they leave the still to the conductive cooling necessary to form sufficient condensate for return to the oil in the still for revaporation therein; because a cleaner separation of hydrocarbons can be effected outside of the still than in it.

In the accompanying drawings, Figures l and 2 taken together (with introduction of short lengths of connecting pipe) constitute a view, partly in perspective (broken away in places) and partly in vertical section, of a distilling apparatus in accordance with the present invention, a series of condensers forming part of said apparatus being shown in Fig. v1 and the still in Fig'. 2; Fig. 3 is a detail view of a portion of the first condenser of the series; Fig;` l is a diagram illustrating 'a modified form of the same condenser; and Fig. 5 is a detail of a, relief 4valve for a pipe in a condenser of such modified form.

The still a is shown in the form of a horizontal cylinder heated by a'number of fire places whose ash pit doors show at b. It is protected against loss of heat externally, the protection shown "consisting of blocks c, brick-work d. and cement e; and it is covered with sheet metal f. There is a pipe g for filling the still with oil and a pipe h for conduct-ing away the vapors.` This vapor pipe is connected with the vapor space of the still a by means of a 'short upright pipe z' valve y) closed.

having a removable cover 7:. A side opening receives the end ot' the vapor pipe L. Below said side opening is a tiap valve whose operating handle is seen at Z; and below said valve is another side opening which receives the pipe m, a continuation ot' which is it'ornied by pipe n having a valve p. In running the tlap valve is open and the At the end o't a run, when steam is intrmluced into the still to expel the vapors therefrom, their positions are reversed.

"lhe pipe (j, which joins the pipe m, is provided with a sa't'ety valve 7' and a vacilum valve s. A pipe If is provided for introducing steam into the still at the end of a run before opei'liug the manholes n tor cleaning out. At' 'fr is the chimney for the tires under the still. At. .fr are holes for pipes to deliver still gases or other fuel gases under the still for burning. This still a with itsl parts and appurtenances, is shown in order to illustrate by way of example a form of still which can well be used to carry -the invention into effect. Other known or suitable forms can be used. The still shown tin Fig. 2 t'or volatilizing the petroleum embodies improvements in respect to its setting which t'orm the subject ot our application ot' October i3, 1.010No. necesi. i

'lhe vapor pipe /1y leads to a condenser in the 'form ot' numerous pipes 2 arranged in parallel between header 3 and chamber 4. In Fig. l the vapor outlet ends ot these pipes are at' a higher level than their vapor inlet ends; so that the condensate, which is formed in each pipe and naturally runs downward, will flow oppositely to the corresponding streani oit vapors. ln order to equalize the tlow ot the vapors among these pipes, the aggregate cross section of the pas-` sages at their narroweft points is proportioned with reference to the passage ot the predetermined volume of vapors per unit of time under a predetermined pressure (tigures 'found useful to be given later); and, in order that the streams may be longer exposed to cooling in pipes ot given length, their average cross sections are made greater than those at said narrowest points and the 'outlet ends ot' said pipe are strictured (or mad-e smaller than said average cross section). Said strictured outlets `may well constitute the narrowest points. Means are provided for automatically releasing the pressure in said pipes should it become excessive at any time. The best arrangement'v is shown in Fig. 3, in which the strictured outlet 5 is formed in the body of a over the end ot' the pipe. There maybe .light valve 6 which rests by its own weight varied, good results have been attained forrv a still holding a thousand barrels of oil up While dimensions and proportions can be to the usual level With an air cooled condenser having fifty siX of the-pipes 2, each eleven feet in length and four inches in eX- ternal diameter (giving about 665 square feet of cooling surface on the closely lapproached'heat conducting-walls of pipes 2). A. circular vapor outlet opening 5 of an inch and a quarterdiameter would sufice for each pipe 2, the vapor pipe 72y having an internal diameter of twelve inches and the, valves 6 Weighing about thirty three' ounces each. f

y The pipes 2 are disposed for cooling by controllable currents of the aeriform coolin'g fluid Howing transversely to and longiltudinally of said pipes. The header 3 is annular and forms part of a passage for the cooling fluid in the middle of the group of pipes 2; While the top of the chamber 4 is a circular disk and obstructs such .passage at its bottom;'and the pipes 2 are inclosed in acasing 7 which ts around the header 3 at the ytop and has inlet openings 8 at the bottom for inflow of air from the sur;

rounding atmosphere.. Each inlet isvprovided With-a valve 9, Which can be opened, Wholly or in'part, or can be completely closed, as may be desired. Air currents are produced in the casing 7 by heat absorbed from the Wallsofpipes 2. The vapor pipe L leads from 'the still directly to the 'chamberf4 inFig. 1. This chamber is. much deeperuthan a' mere manifold or header (the depth represented being about three- Jfourths the length of pipes 2). llt is provided Wit-h a non-conducting (or heat retaining) jacket 10. ln it, resting on the 'grate.11, are pieces 12 of'solid material,

say4 cobble stones of four to eight inches in diameter. The condensate from pipes 2 ovvs down over said stones and is given .by -them aback and forth transverse motion; While the vapors Which rise upvvard between them are similarly deflected; 'and the vapors then pass into the pipes 2 for cooling conductively in distinct. streams. of small diameter. Y

The vapor outlet of the air cooled partial condenser 2, 3, 4 is connected by pipe 13 with the vapor inlet of a second partial condenser-14 composed of numerous pipes set between headers and exposed to the air` for cooling. The vapor outlet from condenser 14 is connected by pipe 15 with a Water cooled condenser, shown in the .form of a coil 16 placed in a Water tank 17, which is supported on Walls 18 and cross beams 19. Thus, as shown, the vapors from the 'still a flow successively through twopartial vcondensers each of them cooled by aeriformruid, and then through a water cooled condenser. f

nordsee The liquid outlets 2O and 21 ot the par-Vv tial condensers are respectively connected through U traps with the Water cooled dravsr of pipes 22 and 23, placed .in water tank 17.

The Water cooled draw off 22 is valved and is connected With outlet 2O by means of a cross Which also serves toV connect said outi let with two other valved pipes'24 and 25 respectively, pipe 24 being a dravv off for condensate from .the 'chamber 4 when said condensate becomes too thick to llow at the temperature of the Water in tank 17, and pipe 25 being a run back'.v leading to the still a.. The pipe 24 is maintained at a higher temperature than the draviT oil" 22. lt may have such higher temperature merely because exposed to the air instead of being immersed in the Water of tank 17'; or additional means of securing higher temperatures can be provided.

At 26 is `a cover to exclude rain, in case thestill stands outof doors; and the partial condenser 14may Well be similarly protect- A valved pipe 2 7 shown in dotted lines can be usedas a run back, if`desircd, between the condenser 14 and the still a.

The vapors generated in still a ass by pipe zy to chamber 4; and on reaching the top of said chamber 4 they are divided into numerous streams, one for each of the pipes 2. rllhese streams flow-in parallel inside the closely approached heat conducting Walls of said pipes' and are severally surrounded by l aeriform 4 fluid (atmospheric air) for cooling andl are further equalized `ramong themselves by the stricturing Whichfthey are given at their outlets by passage through the restrictedopenings 5 (Fig. 3). pressure become excessive, one or more -ot the valves 6 rise and automatically release Should the the pressure, the released vapors passing on to Ycondenser 14. rlhe vaporsflow in opposite 'directions-in-pipes 2 to the corresponding streams of condensate formed by the cooling in the same; and a good opportunity for exchange of hydrocarbons between them is thus afforded, more volatileY hydrocarbons in thecondensate replacing less volatile in the vapors. y l

The How of the aeri-form fluid transversely to and longitudinally of vpipes 2 over and between the same tends to uniform and eiiicient cooling ofthe vapors. Such currents are given torce and direction by their' lateral confinement; While the cooling can be regulated by "opening and closing -t-he valves 9. The vapors are brought into intimate contact in chamber 4 with the condensate 'for interchange of hydrocarbons,

While vthey .are protected against indirectA cooling. Useful but not so good results are.- obtainable Without the pieces 12. The same'- is true with respectl to ,the jacket on chamber 4. For a continuous coi plete distillaP tion of crude petroleum in t' e still a, thev latterI is lled with the proper charge of crude oil (say, a thousand barrels) and is heated by tires underneath; and the heating is continued until Vthe still contents become dry or nearly so, wax 'tailings coming over as the last distillate. During the first part of the run the portion oi3 the crude oil which is more volatile than the intermediate traetion as herein defined is received as distillate; while during the remaincer of the run, which is conducted in two stages, the intermediate and the lubricant (or lubricant and wax yielding) fractions are distilled, the it'oriner with more and the latter with less decomposition (cracking) of constituenthydro :a1-bons. The later of said stages would advantageously be commenced as soon as or shortly after a percentage ot the crude oil equal to said more volatile portion plus said intermediate fraction has'been received as (fiistillatc. During said first part of the run and the earlier ot' said two stages the run back Q5 is open and the draw otl's 22 and 2l are closed. During said later stage the run baci: 25 is closed and the draw offs 22 and 2% are opened one at a time, the i'ormer as long as the distillate from bottom of chamber 4 :is thin enough to tlow at the temperature in pipe 22, and the latter subsequently. The temperature ditllerence between the liquid oil in distillation and the vapors which have passed over to be condensed as distillate. is greater in the previous distillation than in said later stage. ln the former the vapors are made to tlow through the partial condenser 2, 3, 4t before they pass over to be condensed as distillate, all such condensation being pert'orn'ied in the air cooled partial co-ndenser 'll and in the water cooled complete condenser 16 and the ,condensate from condenser 2, 3, l returning by run back Q5 to the oil in distillation in still a; while in said later stage they are condensed as distillate as soonas they have passed out of the still ci. Until then they are protected against conductive cooling by the nonconductingjacket c, 6l, c onthe still; so that the teniperature ditterenee between the liquid oil and the vapors passing.; over is correspondingly; small.

The total flow ot distillate at any time can .largelyibe controlled by regulating the lires; but with equal evaporation per hour the collection of distillate per nour will natw urally be larger when it includes condensate from condenser 3, 4t than when it does not. It is advantageous so .to regulate the still tires that the total flow per hour o't distillate diminishes during` the distillation oi' part at least of the intermediate fraction, as compared with the average o't' such [low duringthe distillation of the more volatile portion of the crude oil, and that the combined tlow per hour from the condensers fl-t and lt (exclusive of condenser 2, 3, 4) during the distillation of part at least of the lubricant (or of the lubricant and wax yielding) traction should equal or exceed the average ot' such flow during the distillation ot' said intermediate fraction; while the average tlow of distillate per hour at the same time from the condenser Q, 3, 4 may well its-eli exceed the same average. lhe flow ot distillate trom each condenser' varies 'from time to time according' to the nature ot the oil; and the llow from condenser 1G may (and perhaps always would) cease before the beginning otI distillation of the intermediate traction. lt so, it should be flowing again beiliore the close of such distillation.

During the distillation of the intermew diate traction and also et the lubricant (or ot' the lubricant and wax yielding) traction the vapors are advantageously cooled in condenser Q, 3, Jlto temperatures intermeiliate LL00o F. and (i000 F. so that the uncoiidensed portion ot said vapors lnay be as 'tree as practical 'trom lubricant. (or lubricant and wax yielding hydrocarlmns. Any desired cuts in any distillate can be made by directingr the stream to different distillate receiv ers in the known manner.

The air inlet.v valves 9 would be more nearly closed at the beginning ol each run, when light hydrocarbons are being distilled, and also at the end olE each run when the volume ot vapors is comparatively small,

than they would be during the interrmidiate part of the run. In other words, the curi rents ot cooling tluid are controlled to increase and decrease in a general way the cooling etl'ect on the vapors according' to the varying volume and tennieraturc of thelatler. Said air inlet valves 9 would also be closed more when the weather cold or windy and less (it at all) when it is warm vapors. They pass, with steam, through the pipes fm, n, to any desired place or receptacle without enteringr the con denser 2. 2%, l, the condenser 14,'01 the condenser 16; so that at the next run the first runuingrs of condensate are not composed in partof hydrocarbons expelled by the steam. So far as concerns the condensate from condenser' 2,3, 1l, as this returns to Still (l, the

presence in it of said hydrocarbons would be of small importance; and it is, therefore, of minor importance tor the valve Z and valved` branch pipe n to be between cen Time after bringing ifnthe still.

Distillation of portion more volatile than the intermediate fraction. as shown by the liquid oil in still a attaining 600 F Distillation of intermediate fraction, as

shown by liquidoil in still a being above 600 F. and the condensate from condenser 2, 3, 4 having a viscosity less than seconds at 100 F. by Saybolts universal viscosimeter Dislillation of lubricant and wax yielding fraction, being residue after removal of intermediate fraction and lighter portion 17 hrs.

Total 54 2o/6o M Flow of distillate.

Distillation of portion more, volatile than intermediate fraction: f

Condenser 16, 147 barrels; condenserA 14, 211 barrels 358 bbls. Average per hour both condenser 18 1/2 bbls. Distillation of intermediate fraction:

Condenser 16, 15 barrels; `condenser 14, 203 barrels '218bb1s. Average per hour both condensers 12 1/10 bbls. Distillation of lubricant and wax yielding fraction Condenser 16, 64 barrels; condenser 14, 113 barrels; condenser 2, 3, 4, 257 barrels Average per hour first two ers Average per hour all three condense Average per hour of rst half of distillation from first two condenser s Average per hour of rst half of distillation from all three condensers Graviiies of distillates.

Distillation of portion more volatile than intermediate fraction.:

Condenser 16:

19 20/60 hrs.

1s hrs.

434 bblS.

11 1/10 bbls. 27 1/10 bbls.

17 25/100 bbls.

37 1/10 bblS.

Lightest 7/10 B. C Heaviest 48 8/10 B.

ondenser Lightest 63 5/10: B. Heaviest 405/10 B. Distillation of intermediate f ac on.

Condenser 16 Lightest 57 B. Heaviest 47 B. Condenser 1 i o Lightest 405/10 B. Heaviest 34 S/10 B. Distillation of lub fraCction y 1G ondenser LightesL 55 7/10 B. Heaviest 41 B. Condensei 1 Lightest 37 6/10 B. Heaviest 28 B. Condenser 3, 4

Lightest 31 B. Heaviest received by water cooled pipe 22 11 B.

.'l'empcraturcs after bringing in, still.

Lowest 168 F.

, Highest 480 F. Temperature difference, average 97 5/10 F. Vapors leaving;r still a (in pipe i) Lowest 193 F. Highest 560 F'.

invasie Distillation of intermediate fraction:

Oil in still a:

Lowest 600 F. Highest 700 F. Vapors passing over to be condensed as distillate (in header 3) Lowest 470 F.

Highest 570 F. Temperature difference, average 151 F. Vapor-s leaving still a (in pipe i) Lowest 560 F.,

Highest 660 F.

Distillation of lubricant and Wax yielding fraction Oil in still a.'

Lowest 691 F. Highest (See note). Vapors passing over to be condensed as distillate (in pipe i) Lowest 644 F.

Highest 810 F.

Temperature difference, average (See note). Vapors after first fractional condensation as distillate (vapors in header 3) l Lowest 317 F. Highest 607 F.

Nonne-By an accident the temperatures in the liquid space of still a were not observed at the last seven periods ot hourly observation. From other experience it isvestimated that the highest temperature in the liquid space 1n the still was about 850 F.; and (using so estimated temperatures for seven of the eighteen intended observations) the average temperatureV dierence during the dist1llat1on of the lubricant and wax yielding fraction is estimated to have been 46 F. The average temperature difference at theaeleven actual observations was 50 F.

A The heating ofthe still was continued 4 for three hours after the. distillate ceased to flow from condensers 1 6 and 14 and for two hours after that from condenser 2, 3, 4 was turned into pipe 24 (wa-X tailings). ln the last hour of flow from condenser 2, 3, 4 through pipe 22 only one barrel of distillate (gravity 11 B. at 60 lF.) was received. ln the hour previous half a barrel (gravity 55 7 /10 B.) was received from condenser 16, one barrel (gravity 35 BL) from condenser 14, and twobarrels (gravity 18 5/10 B.) from condenser 2, 3, 4.

Distillate did not low from the condenser 16 in the distillation of the intermediate fraction during ten hours, and in the previous distillation during four hours. Distillate commenced to flow first from condenser 16 and was running two hours and twenty minutes before it commenced t0 tlew from the draw off 23 of condenser 14. lhese hours of no low in one or other condenser are taken in in estimating the average flow as given in table. More than half the distillate in the distillation of the lubricant and wax yielding fraction was received inthe lirst six hours; and the flow during such six hours is the basis for the average. flow per hour of first half of distillation of vsaid fraction. Twelve thousand two -hundred pounds of colte were removed from the still at the end of the run.

@bservations were made at each hour of the clock, the first one being twenty minutes after bringing in the still.. The gravities shown are those of samples taken at the times of observation. 'llhe temperatures given as lowest and as highest respectively are the lowest andhighest of those so taken. The average temperature differences are the quotients from adding together the diderences at the times of observation and: dividing by the number of observations. In practical working it is-l'umecessary to ascertain temperatures; since observation of the distillates or distillates and returning condensate will give sufficient information to an experienced stillm'an; but resort can be had to thermometric readings, should it be at any time desired.

Should it be so desired, the earlier stage of the distillation of the undistilled residue composed of the intermediate and the lubricant (or lubricant and wax yielding) itrac tions of the crude oil can be prolonged into the distillation of the latter traction` said stage bein-g terminated while the desired portion, not less than twenty ive'per cent., of said fraction remains in the still.

Should it be desired not to conduct the complete distillation of the crude oil Ain the still a, all, or any part, of the portion more volatile than the intermediate fraction can be distilled oit in another still or stills in any known or suitable Way and the residual oil can then be `subjected. to uninterrupted distillation in the still a in said two stages; and, if preferred for any reason, the distillation can be carried further before transnfer to the still 0;, provided the residual oil to be subjected to distillation uninterruptedly in4 said two stages shallv contain at `least forty per cent. of the lubricant (or of the lubricant and wax yielding) fraction of the crude oil.

In Fig 4 a jacketed chamber 30 with pieces 12 of solid material loosely piled together receives the vapors from still a and is provided with the same run baclt and draw off pipes 22, 24 and 25 as the chamber 4. Fromthe upper part of said chamber the vapor flows by pipe 3l into the annular header 32, which corresponds with the i header 8 of Fig. 1, except that it now forms the inlet to'pipes 2 instead of the outlet therefrom. The vapors beingmade to llow downward through the pipes 2 equalize themselves among the several streams there in, without requiring the latter to be liniited in their aggregate cross section; because the tendency is toI check the flow of vapors through the hotter pipes; but strictured outlet openings and means for releasingpressure automatically can be used, as indicated (for example) in Fig. 5; in which a valve having a restricted opening 34 therein is upheld by the slight pressure of aspring The condensate from pipes 2 falls into pan 39 andlows by pipe .l0 to the perforated annu-lar pipe 36; which distributes it over the top of the loose pile ot pieces 12. The vapors uncondensed in chamber 30 and pipes 2 pass through chamber 37 and pipe 3S into condenser 11i; which corresponds with the similarly `rnumbered part in Fig. 1.

With the arrangement of Fig. 4, during the earlier stage of the uninterrupted distillation the vapors pass over from the lower ends ot' pipes 2 to be condensed as distillate; and the temperature difference between the liquid oil in distillation and such vapors would be measured by thermometers in said oil and in the vapors in the top of chamber 37 respectively.

As employed in this specification, the lubricant (or lubricant and wax yielding) fraction and the intermediate fraction taken together ot any given crude petroleum are represented by the percentage by volume of said crude petroleum which remains in the still when the stills contents attain a tem perature of 000O F. (or the temperature commencement ol cracking in case it should be lower than 600o F.) in a distillation of said crude petroleum in the ordinary way under atmospheric pressure without introduction of aerform fluid into the still; and the lubricant (or lubricant andwax yielding) fraction is represented by the percentage by volume of said crude petroleum which remains inthe still when portions ot' distillate from the outlet of the customary water cooled condenser lirst exhibit either a viscosity as high as (55 seconds at 100o F. by Saybolts universal viscosimeter or a cloud at a temperature as high as 50 F. (whichever characteristic is first` exhibited) in a distillation oi" said crude petroleum with introduction into the liquid oil of tree steam in suitable volume to prevent cracking. For concord'ant results said distillations (or assays) must always be performed in the same manner; and they may well be performed by using such a laboratory apparatus as is shown 1n eut No. 1280 in the catalogue of E. Ifl. Sargent d', Company, of 145 Lake street, Chicago, Illinois, for 1908. It has a copper still of cheese box form heated by a gas flame underneath; and it is provided. with means for introducing free steam intothe liquid oil in the still. A. still with a charging capacity of about ten liters would be large enough; and it should receive a charge about equal to its capacity.

In the distillation under atmospheric pressure without introduction of aeriform fluid into the still steam is, ot course, not admitted. The heat may be so regulated that distillate is received from the condenser at the uniform rate of about eight per cent. by volume per hour of the charge of crude oil. The distillate may be received in two per cent. portions; and they (or such of them as may be necessary) should be tested for flashing points by the closed cup method, after removal of hydrogen suld, when this is present. The temperature of the oil in the still at the completion of each portion should be noted. When the flashing points begin to exhibit a progressive re cession, it will be known that substantial.

hydrocarbon distillate is received from the cracking has set in; and the temperature at the completion of the portion of maximum flashing point may be taken to be the com-- mencement of cracking. Should this temperature be below 6000,19., the percentage of the crudeoil then remaining in the still represents the intermediate and lubricant '(or lubricant and wax yielding) fractions of the crude oil (taken together), the percentage previously collected as distillate representing the more volatile portion of the same crude oil. Should this temperature of conimencement of cracking be above 600O F., the percentages when the liquid oil attains 600 F. are to be taken.

In the distillation with introduction of free steam into the liquid oil the charge of crude petroleum (as before) should correspond witli the charging capacity of the still; the heat may be so regulated that condenser at the uniform rate of about fifteen per cent. by volume per hour ot' the charge of crude oil; and the free steam supply may be so regulated that the stream. from the condenser conta-ins water of con-v densation equal in volume to from a third to a half of said hydrocarbon distillate. The steam may be dry and saturated; or it may be slightly superheated. The distillate may be received in two per cent. samples; and they (or such of them as maybe necessary) should be tested for viscosity and (when the petroleum yieldsparaiin wax) for cloudI (paraiiin wax content) also. When a portion exhibits either a viscosity as high as 65 seconds at. 100O F. by Saybolts universal viscosiineter or a cloud at a temperature as high as 50O F. (whichever characteristic first appears) thepundistilled residue plus said portion represents with sufficient accuracy the lubricant (or lubricant and wax yielding) fraction of .the petroleum. T he difference between it and the percentage representing the intermediate and lubricant (or lubricant and wax yielding) fractions taken together (as shown by previously mentioned assay) represents the intermediate lfraction of the crude petroleum. The portions of distillate to be test-- ed for viscosity (or viscosity and cloud) should be separated by settling and decan- 'tation from the accompanyingwater before they are so tested.

In consequence of oiiicial requirement of division, we filed two divisional applications on April 18, 1911;"which have been oiiicially numbered 621,904 and 621,905, respectively.

, The subject-matter of application 621,904

corresponds with claims 15 to 31 (both inelusive.) and 36 to 60 bothinclusive) of our original specification as filed on October 4, 1909; `and the subject-matter of application 621,905 corresponds with claims 32 to 35 (both inclusive)`of the so filed Speciication..

Said claims numbered 15 .'to60 in'our so filed specification have-,sof course, been withdrawn from the present-(parent) applicaor lubricant and Wax yielding) fraction of the crude petroleum to the extent of forty.y

' per cent. of said fraction as a minimum, by heating such undistilled petroleum to the temperature necessary to distil component hydrocarbons, cooling the evolved vapors first to temperatures at which a partial condensation is effected and a residue left of un- `condensed vapors and then to lower temperatures for effecting condensation of such residual vapors, returning condensate from the first mentioned cooling to the oil in distillation and drawing off as distillate condensate formed by said further cooling, and so continuing until the oil in distillation has 4been substantially reduced in volume yet not to such extent that it contains less than twenty tive per cent. Aby volumev of said lubricant (or lubricant and waX yielding) fraction of the crude petroleum, and thereupon, while the so reduced oil contains said :lubricant (or lubricant and wax yielding) fraction to the, extent of twenty tive per cent. of said fraction of the crude petroleum as a minimum and while the distillation is carried on uninterruptedly, cooling the vapors evolved from the so reduced oil lfirst to temperatures at which a partial condensation is effected and a residue left of uncondensed vapors and then to lower tempera- `tures for eiecting condensation of such residual vapors and drawing 0H' condensate formed by said partial condensation of vapors evolved from "the so reduced oil and condensate formed by said further cooling of the residual vapors as distinct distillates.,v

and continuing the distillation with such cooling of vapors'and such drawing oi of distillates until a substantial quantity of condensate with a viscosity Aas high as 65 secp onds at 100 F. by Saybolts universal viscosime'ter has been collected as distillate,v the last mentionedv distillate being formed lfrom vapors whose average temperature'at the place where they pass over to be condensed as such distillate diers from the average contemporaneous temperature :of they oil in distillation less than the average temperature of the vapors which form the i'irst men'- tioned distillate in the earlier stage of the distillation at the place where they pass over f to be condensed as such distillate diii'ers `from the average contemporaneous temperature of the oil in distillation in said earlier stage, substantially as described.

2. rllie process of distilling petroleum in a form which contains the defined lubricant (or lubricant and wax yielding) fraction of the crude petroleum to the extent of forty per cent. of said fraction as a minimum, by heating such undistilledpetroleum to temperatures above 450o F., cooling the evolved vapors to temperatures above 400 F. and more than 50 F. below the contemporaneous temperatures of the oil in distillation and. then to lower temperatures, returning condensate so formed above 00D F. to the oil in distillation and drawing ofi1 as distillate condensate formed by the further cool ing of vapors whose temperatures are above 4000 F. at the place where they pass `over to be condensed as such distillate, and so continuing until the oil has been substantially reduced in volume yet not to such extent that it contains lessthan twenty five per cent. by volume of saidlubricant (or-lubri cant andwaX yielding) 'fraction or the crude petroleum', and thereupon, while the so reduced oil contains said lubricant (or lubricant and waX yielding) fraction to the extent of twentyfive per cent. of said fraction of the crude petroleum as a minimum and while the distillation is carried on uninten ruptedly, cooling the vapors evolved from the so reduced oil first to temperatures at which a. partial condensation is effected and Aa residue left of uncondensed vapors and then to lower temperatures for effecting condensation of such residual vapors and drawingoft'condensate formed by said partial condensation o vapors evolved from the so reduced oill and condensate formed by said further cooling of the. residualvapors as distinct distillates, and continuing the distillation with such cooling of vapors and suchdrawing off of distillatesuntil. a substantial quantity of condensate with a viscosity as high as (Bseconds at 100 F. by

Saybolts universal viscosimeter has been collected as distillate, the last mentioned distillate being formed -fromvapors whose av orage temperature at the place where they pass over to be condensed-as such distillate dilers :from the average contemporaneous I temperature offthe oilrin distillation less than the average temperature of the vapors which form the first mentioned distillate in the earlier stage of the distillation at the place Where they pass over to be condensed as such distillate ydiffers from the average contemporaneous temperatureof the oil in distillation in said earlier stage, substantially as described.

to the high temperatures necessary to distil hydrocarbons. withboiling points above the defined temperature of-commeneeinent of cracking of said crude petroleum, cooling the evolved vapors first to temperatures` less than twenty five per cent. by volume of said lubricant (or lubricant and wax yielding) fraction of the crude petroleum, and thereupon, while the so reduced oil contains said lubricant (or lubricant and wax yielding) fraction to the extent of twenty Vfive per cent. of said fraction of the crude petroleum asa minimum and while the distillation is carried on-iininterruptedly, cooling the vapors evolved from the so reduced oil first to temperatures at which a partial condensation is effected and,l a residue left of uncondensed vapors and then to lower temperatures for` eflecting condensation vof such residual` vapors and drawing ofi' condensate formed by said partial condensation of vapors evolved from the so reduced oil and condensate formed byy said further cooling of' the residual vapors as` distinct distillates, and continuing the distillation with such cooling oi vapors and such drawing off Aof distillates until a substantial quantity of condensate with a viscosity as high as 65- dcnsed as such distillate differs from the,V

average contemporaneous temperature of the oil in distillation less than the average temperature of the vapors which form the lfirst mentioned idistillate in the earlier stage of the distillation at the place where they pass over to be condensed -as such distillate differs from the average contemporaneous temperature of the oil in distillation in said earlier stage, substantially as described.

4. The process of' distilling petroleum in the form an undistilled residue of crude petroleum which contains the defined lubri cant (or lubricant and wax yielding) fraction of said crude petroleum to the extent of forty per cent. of said fraction as a niinimum, by heating such undistilled residue to the high temperatures necessary to distil hydrocarbons with boiling points above the defined'temperature of commencement of cracking -oi saidicrude petroleum, cooling the evolved vapors first to temperatures above 4.00o F,andY more .than 50"4 F. below the contempo-raneous temperatures of the oil in distillation and then to lower temperatures, returning condensate so formed above 400 F. to the oil in distillation and drawing off as distillate condensate formed by the further cooling of vapors whose temperatures are above 1:00o F. at the place where they pass over to be condensed as such distillate, and so continuing until the cil in distillation has been substantially reduced in volume yet not to such extent that it contains less than twenty five per cent. of said lubricant. (or lubricant and wax yielding) fraction of the crude petroleum, and thereupon, while the so reduced oil contains said lubricant (or lubricant and wax yielding) fraction 'to the extent of twenty five per cent. of said fraction of the crude petroleum as a minimum and while the' distillation is, carried on uninterruptedly, cooling the vapors evolved from the so reduced oil first to temperatures above Li00O F. and more than 500 l?. below the contemporaneous tempera-tures of the' oil in distillation and then to lower temperatures and drawing ofi condensate formed above 400o F. and condensate formed by further cooling as distinct distillates, and continuing the distillation with such cooling of vapors and such drawing 0H of distillates until a substantial quantity of condensa-te formed 1 above 400O F. has been collected as distillate the last mentioned distillate being `formed from vapors whose average temperature at the` place where they pass over to be condensed-as such distillate diders from the average contemporaneous temperature of the oil in distillation less than the average temperature of the vapors which 'form they first mentioned distillate inthe earlier stage of the distillation at the place where they pass over to be condensed-as such distillate differs from the average contemporaneous temperature ofthe oil in distillation in said earlier stage, substantially as described.

5. IThe process of distilling petroleum in a form which contains the defined lubricant f (or lubricant and wax yielding) fraction of the` crude petroleum to the extent of forty' per cent. of said fraction as a minimum, by

`heating such undisti'lled petroleum, to the temperature necessary to distil component hydrocarbons, cooling the evolved' vapors rst to temperatures at which a partialcondensation is effected and a residue leftof uncondensed vapors and then to lower temperatures lfor effecting' condensation of such residual'vapors, returning condensate ,from the first mentioned cooling to the ,oil in c, distillation and drawing ofl as `distillate condensate formed by said further cooling, and so continuing until the oilv in distillation has beenlsubstantiallyV reduced inv volume yet Vnot to such extent that it contains less than tweutv live percent. by volume of said lubri- Lor/ases cant (or lubricant and wax yielding) fraction of the crude petroleum, and thereupon,

while the so reduced` oil contains said lubricant (or lubricant and wax yielding) frac- -by said partial condensation of `vapors evolved from'the so reduced oil and condensate formed by said further cooling of' the residual vapors as distinct distillates, and continuing the distillation with such cooling of vapors and such drawing o' of distillates until a substantial quantity of condensate with a viscosity as high' as 65 seconds at 100O El by Saybolts universal viscosimeter has been collected as distillate, the

last mentioned distillate being formed fromv vapors whose average temperatur-e at the place where they pass over tosbe condensed as such distillate differs from the average contemporaneous temperature of the oil in distillation less than the average temperature of the vapors which form the first mentioned distillate in the earlier stage of the distillation at the place where they pass over to be condensed 'as such distillate diers` from the average contemporaneous temperature ot' the oil in distillation in said earlier stage, and the cooling of the .vapors to form condensate returning to the oil in distillation in the earlier stage of the distillation as well as the cooling of vapors to form condensate collected as distillate in both stages being edected by passing said vapors between closely approached heat conducting surfaces hydrocarbons, .cooling the evolved vapors l first to temperatures at which a partial condensation is effected and a residue left of uncondensed vapors and then to lower Vtemy peratures for effecting condensation of such residual vapors, returning condensate from the rst mentioned cooling to the oil. in distillation and drawin off' as distillate condensate formed by said lfurther cooling', and

so continuing until the oil in distillation has been" substantially reduced in volume yet not to such extent that it contains'less than twenty five per cent. by volume of said lubri,

tion to the extent of twenty tive per cent. of

said fraction of the crude petroleum as a minimum and while the distillation is carried on uninterruptedly, coolingithe vapors evolved from the so reduced oil first to temperatures at which a partial 4condensation is eil'ected and a residue lett of uncondensed vapors and then to lower temperatures for effecting condensation of such residual vapors and drawing o'tll condensate formed \by said partial condensation of vapors evolved from the so reduced oil and condensate formed by said further cooling of the residual vapors as distinct distillates, and continuing the distillation with such 2o cooling of vapors and such drawing ott' of distillates until a substantial quantity oi. condensate with a viscosity as high as G5 seconds at 100o F. by Saybolts universal viscosimeter has been collected as distillate, the

last mentioned distillate being formed Jfrom vapors whose average temperature at the place where they pass over to be condensed as such distillate ditlers from the average contemporaneous temperature of the oil in so distillation less than the average temperature of the vapors which form the first mentioned distillate in the earlier stage ot the distillation at the place where they pass over to be condensed as -such distillate Adiffers from the average contemporaneous temperature ot' the oil in distillation in said earlier stage, and the average volume of distillate received p er hour being larger in the earlier part at least ot .said later stage than it is in 4o said earlier stage, substantially as described.

7. The brocess of distilling petroleum in a form which contains the defined lubricant (or lubricant and wax yielding) 'fraction of the crude petroleum to the extent of forty per cent. ot said traction as a minimum,

by heating such undistilled petroleum to the temperature necessaryto distil component hydrocarbons, cooling the evolved vapors first to temperatures at which a partial condens-ation is effected and a residue lett ot' uncondensed vapors and then to lower temperatures 'for effecting condensation of such residual vapors,- returning condensate from the first mentioned cooling to the oil in distillation and drawing otl as distillate condensate formed by said further cooling, and so continuing until the oil in distillation has been substantially reduced in volume yet not to such extent that it contains less than twenty tive per cent. by volume of said lubricant (or lubricant and wax yielding) fraction of the crude petroleum, and thereupon, while the so reduced oil contains said lubricant (or lubricant and wax yielding) fraction to the extent of twenty five per cent.

of said fraction of the crude petroleum as a mininnnn and while the distillation is carried on uninterruptedly, cooling the vapors evolved from the so reduced oil first to temperatures at which` a partial condensation is effected and a residue lett o uncondcnsed vapors and then to lower tempe atures for ettecting condensation of such residual vapors and drawing oi'f condensate formed by said partial condensation of vapors evolved from the so reduced oil and condensate formed by said further cooling of the residual vapors as distinct distillates, and continuing the distillation with 'such cooling of vapors and such, Vdrawing oil' oi distillatcs until a substantial quantity of condensate with a viscosity as high as 65 seconds at 100 F. by Saybolts universal viscosimeter has been collected as distillate, the last mentioned distillate being formed from vapors whose average temperature at the place where they pass over to be condensed as such distillate differs from the ave `age contemporaneous temperature of the oil in distillation less than the average temperature o'l the vapors which form the iirst mentioned distillate in the earlier stage ot' the distillation at the place where they )ass over to be condensed as such distillate dihers from the average contcmporaneous temperature otl the oil in distillation in said earlier stage, and the partial condensation in one at least of the two stages ot' the distillation being controlled by alterations ot cooling etfect distinct from those produced by regulation of the still tires, substantially as described. i

8, The process of distilling petroleum in a form which contains the dclined lubricant (or lubricant and wax yielding) traction of the crude petroleum to the extent ot' forty per cent. ot' said traction as a minimum, by heating such undistilled petroleum to the temperature necessary to distil component hydrocarbons, cooling the evolved vapors first to tempe 'atures at which a partial condensation is etlected and a residue lett oit uncondensed vapors and then to lower temperatures for etl'ecting condensation of such re- V sidual vapors, returning condensate from the first mentioned cooling to the oil in distil-` lation and drawing oli' as distillate conden- 'sate formed by said further cooling, and so continuing until the oil in distillation has been substantially reduced in volume yet not to such extentthat it contains less than twenty five per cent. by volume of said lubricant (or lubricant and wax yielding) fraction of the crude petroleum, and thereupon, while the so reduced oil contains said lubricant or lubricant and wax yielding) fraction to the extent of twenty tive per cent. of said traction of the crude petroleum as a minimum and while the distillation is carried on uninterruptedly, cooling the vapors evolved from the so reduced oil first to temperatures at which a partial condensation is effected and a residue left of uncondensed vapors andothen to lower temperatures for effecting condensation of such seconds at 100o F. by Saybolts universal viscosimeter has been collected as distillate, the last mentioned distillate being formed from vapors whose average temperature at the place where they pass over to be condensed as such distillate differs from the average contemporaneous temperature of f the oil in distillation less than the average temperature 'of' the vapors which form the first mentioned distillate in the earlier stage of the distillation at the place where they pass over to be condensed as such distillate dilers from the average contemporaneous temperature of the oil in distillation invsaid earlier stage, and the condensate formedby the partial condensation of vapors in one at least of the two stages of.' the distillation being brought into intimate Contact. with the vapors for interchange of hydrocarbons, 'substantially as described. Y

9. The process of distilling petroleum in a form which contains thedened lubricant (or lubricant and wax yielding) fraction of the crude petroleum to the extent of fort-y per cent. of said fraction as a minimum, by heating such undistilled petroleum to the temperature necessary to distil component hydrocarbons, cooling the evolved vapors first to temperatures at which a partial condensation is effected and a residue left of uncondensed vapors yand then to lower temperatures for effecting condensation of such residual vapors, returning vcondensate from the first mentioned cooling to the oil in distillation and drawing off as distillate condensate formed by said further cooling, and so continuing until the oil in distillation has been substantially reduced in volume yet not to such extent that it contains less than twenty five per cent. by volume ofsaid lubricanty (or lubricant and wax yielding)` fraction, of the crude petroleum, and thereupon, while the so reduced oil contains said lubricantl (or lubricant and .wax yielding) fraction to the extent of twenty live per cent.. of said fraction of the crude petroleum as a minimum and while the distillation is`carried on uninterruptedly cooling the vapors evolved from the so reduced oil first to temperatures at which a partial condensation is edected and a residue left of uncondensed vapors and then to lower temperatures for effecting condensation of such residual vapors and drawing olf condensate formedby said partial condensation of vapors evolved from the so l reduced oil and condensate formed by said further cooling of the residual vapors as distinct distillates, and continuing the distillation with such cooling of vapors and such drawing off of distillates until a substantial quantityof condensate with a viscosity as high as seconds at 100o F. by

Saybolts universal'viscosimeter has been collected 4as distillate,'the last mentioned distillate being formed from vapors whose average temperature at the place where they pass over to be condensed as such distillate differs :trom the average contemporaneous temperature of the oil in distillation less than the average temperature of the va` Aa form which contains the defined lubricant (or lubricant and wax yielding) fraction of the crude petroleum to the extent of forty per cent. or" said fraction as a minimum, by heating such undistilled petroleum to the temperature necessary to distil component hydrocarbons,- cooling the evolved vapors first to temperatures at which a partial condensation is effected and a residue left ot uncondensed vapors and then to lower temperatures for effecting condensation of such residual vapors, returning condensate from the first mentioned cooling to the oil in distillation and drawing off as distillate con-y densate formed by said further cooling, and so continuing until the oil in distillation has been substantially reduced in volume yet not to such extent that it contains less-than twenty live per cent. by volume of said lubricant (or lubricant and wax yielding) fraction of the crude petroleum, and thereupon, while the so reduced oil contains said lubricant (or lubricant and .wax yielding) fraction to the extent of twenty five per cent. of said fraction of the crude petroleum as a minimum and while the distillation is carried on uninterruptedly, cooling the vapors evolved from the so reduced oil lirst to temperatures atwhich a partial condensation is eli'ected and a residue left of unconden-sed vapors and then to lower temperatures or effecting condensation of such residual vapors and drawing oft condensate formed by said partial condensation of vapors evolved from the so reduced oil and condensate formed by said further cooling of the residual vapors as distinct distillates, and continuing the distillation with such cooling of vapors'and Isuch drawing ott of.

distillates until a substantial quantity of condensate With a` viscosity as high as G seconds at 100O F. by Saybolts universal viscosimeter has been collected as distillate, the last mentioned distillate being 'formed `from vapors Whose average temperature at the` place where theypass over to be condensed as such distillate differs from the average contemporaneous temperature of the oil in distillation less than the average temperature of the vapors which form the iirst l mentioned distillate in the earlier stage of the distillation at the place where they pass over to be condensed as such distillate differs from the average contemporaneous temperature of the oil in distillation in said earlier stage, and the cooling of the vapors to form condensate returning to the oil in distillation in the earlier stage of the distillation as well as the cooling of the va ors to form condensate Withdrawn as distillate in the later-stage being performed by dividing the body of vapors evolved in the still into numerous streams separated from each other by heat conducting Walls and causing currents of aeriform fluid to flow over said Walls 'transversely to and between said streams of vapors, substantially as described.

y 11. The process of distilling petroleum in a form which contains the defined lubricant or lubricant and wax yielding) fraction ot the crude petroleum to the extent of forty per cent. of said fraction as a minimum, by heating such undistilled petroleum to the temperature necessary to distil component hydrocarbons, cooling the evolved vapors first to temperatures at which a partial condensation is effected and a residue left of uncondensed vapors and then to lower temperatures for effecting condensation of such residual vapors, returning condensate from tbe first mentioned cooling to the oil in distillation and drawing ofil as ydistillate condensate formed by said further cooling, and so continuing until the oil in distillation has been substantially reduced in v'olume yet not to such extent that Ait contains less than twenty five per cent. by volume ot said lubricant (or lubricant and Wax yielding) fraction ot the crude petroleum, andl thereupon, while .the so reduced oil contains said lubricant( or lubricant and wax yieldingl fraction to the extent of twenty five per cent. of said fraction `of the crude petroleum as a minimum and while the distillation is carried o-n uninterruptedly, cooling the vapors evolved from the sc reduced oil .first to temperatures at which a partial condensation is effected and a' residue left of uncondensed vapors and then to lower Vtemperatures for effecting condensation ot' such residual vapors and drawing oil condensate formed by said partial `condensation of vapors evolved from the so reduced oil and condensate` formed by said further cooling of the residual vapors as distinct distillatcs, and continuing the distillation with such coolino' of vapors and such drawing oil' of dlstillatcs until a Substantial quant-ity off condensate with a viscosity as high as G5 seconds at 100o F. by Saybolts universal viscosimeter has been collected as distillate,` the last mentioned distillate being formed from vapors whose average temperature at the place where, they pass over to be condensed as such distillate differs from the average contemporaneous temperature of the oil in distillation less than the average temperature of the vapors which form the first mentioned distillate in the earlier stage of the distillation at the place where they ass over to be condensed as such distillate dit iers from the average contemporaneous temperature of the oil in distillation in said earlier stage, and a number of condensates being formed in both stages by successive coolings ot' the vapors by means of acritorm fluid and also a condensate by cooling the residual vapors by means of a liquid, substantially as described.`

12. The process of distilling petroleum in a form which contains the defined lubricant (or-lubricant and wax yielding) fraction of the crude petroleum to the extent of forty per cent. ot' said Jfraction as a minimum, by heating such undistilled petroleum to the temperature necessary to distil component hydrocarbons, cooling the evolved vapors first to temperatures at which a partial condensation is effected and a residue left ol uncondcnsed vapors and then to lower temperatures 'for effecting' condensation of such residual vapors, returning condcnsatc from the, first mentioned cooling to the oil in distillation and drawing' off as distillate condensate 'lormcd by said further cooling, and socontinuing until the oil in distillation has been substantially reduced in volume yet not to such extent that it con-` tains less` than twenty five per cent. by volume of said lubricant (or lubricant and fax yielding) fraction ot the crude petroleum,y

and thereupon. while theso reduced oil contains said lubricant (or lubricant and wax yielding) fraction to the extent of: twenty five p er cent. of. said fraction ot the crude petroleum as a minimum and while the distillation is carried on uninterruptedly, cooling the vapors evolved frorn the so reduced oil first to temperatures at which a partial condensation is effected and a residue Etat:

vleft ofuiicon'densed vapors and then to lower temperatures for veffecting condensation of such residual vapo-rs and drawing off condensate formed by said partial condensation of vapors evolved from the so reduced oil and condensate formed by said further cooling of the residual vapors as distinct distillates, and continuing the distillation with such cooling of vapors and such drawing o' of distillates `until a substantial quantity of condensate with a viscosity as high as t'seconds at 100 F. byl Saybolts universal viscosimeter has been collected as' distillate, the last mentioned distillate being formed from vapors whose average temperature at the place where they pass over to be condensed as such distillate differs from the average contemporaneous temperature of the oil in distillation less than the average temperature of the vapors which form the first mentioned distillate in the earlier stage of the distillation at the place where they pass over to be condensed as such distillate differs from the average contemporaneous temperature of the oil in distillation in said earlier stage, the cooling of the vapors to form condensate returning to the oil in distillation in the earlier stage of the distillation as well as the coolingof vapors to form condensate ofthe specified viscosity collected as distillate in the later stage being effected by means of aeriform fluid, and the condensate of the specified viscosity collected .as distillate toward the end of the first to temperatures at which a partial con'- densation is eected and a residue left of uncondensed vapors land then to lower temperatures for effecting condensation of such residual vapors, returning condensate from the first'mentioned cooling to the oil in distillation and drawing off as distillate condensate formed by said further cooling, and so continuing until the oil in distillation has been substantially reduced in volume yet not to such extent that it contains less than twenty five per cent. by volume of said lubricant (or lubricant and wax yielding) fraction of the crude petroleum, and thereupon, while the so reduced oil contains said lubricant (or lubricantand wax yielding) `fraction to the extentof twenty i'ive per cent. of said fraction of the crude petroleum as a minimum and while the distillation is car- .yapors vto the next in series,

Aried on uninterruptedly, cooling the'vapors evolved from the so-reduced oil first to temperatures at which a partial condensation is effected and a residue left of uncondensed vapors and-then to lower temperatures for effecting condensation of such residual vaporsand'drawing off condensate formed by said partial condensation of vaporssevolved from the so reduced oil and condensate formed by said further cooling of the residual vapors as distinct distillates, andcontinuing the distillation with such cooling of vapors and such drawing off of distillates until a substantial quantity of condensate with a viscosity as high as 65 seconds at 100 F. by Saybolts universal viscosimeter has been collected as distillate, the .last mentioned distillate being formed from vapors whose average temperature at the place where they pass over to -be condensed as such distillate differs from the average contemporaneous temperature of the oil'in distillation less ,than the average temperature of the vapors which form the first mentioned distillate in theearlier stage of the distillation at the place where they pass over to be condensed as such distillate differs from the averageicontemporaneous temperature ofthe oil in distillation in said earlier stage, and the condensate of the specified viscosity collected as distillate toward the end of the distillation being drawn off` through a pipe of higher temperature than the pipe through which such condensate has previously been described.

14. Apparatus for distilling petroleum in a form which'coiitainsthe defined lubricant (or lubricant and wax yielding) fraction of the crude petroleum to the extent of forty per centof said :traction as a minimum in ordei` to obtain distillate with a viscosity as drawn off, substantially as ico high as 65 seconds at`100O F. by Saybolt"s universal viscosimeter as well as distillate of lower viscosity, which apparatus consists ,of a still, a number of sets of condensing appliances which are cooled by means of aeriform Huid and are arrangedin series so that oneY set communicates with the vapor space of the still and delivers its residual devices4 for reiis turning condensate from one set at least of said condensing appliances to said still, de-

vices for drawing oli' condensa-te fromeach cset of said condensing appliances as distil-` late, and condensing appliances for receiving residual vapors from previously mentioned condensing appliances arranged to' be cooled by means ot a liquid, substantially as described.

15. Apparatus for distilling petroleum in a form which containsthe defined lubricant (or lubricant and wax' yielding) fraction of the crude petroleum to the extent of forty per cent. of said fraction as a minimum in order to obtain distillate with a viscosityas high as 65 seconds at 100o F. by Saybolts universal viscosirneter as well as distillate of lower viscosity, which apparatus consists of a still, condensing appliances which are cooled by means of aeriforrn fluid and which communicate with the vapor space of said still, devices for returning condensate from such condensing appliances tosaid still, two sets of devices for drawing off condensate as distillate from such condensing appliances arranged to be maintained one set at a higher temperature than the other set, and condensing appliances for receiving and cooling residual vapors from previously mentioned condensing appliances, substan tially as described.

16. Apparatus for distilling petroleum in a form which contains the defined lubricant (or lubricant and wax yielding) fraction'of the crude petroleum to the vextent of forty per cent. of said fraction as a minimum 1n order to obtain distillate with a viscosity as high as 65 seconds at 100o F. by Saybolts universal viscosiineter as well as distillate of lower viscosity, which apparatus consists of a still, condensing appliances communicating with the vapor space of said still, devices 'for returning condensate from such condensing appliances to said still, two sets of devices for drawing oil' condensate as dis tillate from such condensing appliances arranged to be maintained one set at a higher temperature then the other set, and condensing appliances for receiving and cooling residual vapors from previously inentioned condensing appliances, substantially as described. v

In testimony whereof we have signed our names to this specification in the presence of two subscribing witnesses.

JOI-IN l/V. VAN DYKE. WILLIAM M. IRISH. Witnesses:

H. A. ELLIS,

EDW. C. ESTERLY. 

